Safety Circuits - Minolta Di850 Service Manual

SAFETY INFORMATION

SAFETY CIRCUITS

This machine is provided with the following safety cir-
cuits to prevent machine faults from resulting in seri-
ous accidents.
[1] Overall protection circuit
[2] L2 and L4 (fixing heater lamps) overheating
prevention circuit
These safety circuits are described below to provide
the service engineer with a renewed awareness of
them in order to prevent servicing errors that may
impair their functions.
[1] Overall Protection Circuit
1. Protection by CBR1 and CBR2 (circuit
breakers)
CBR1 interrupt the AC line instantaneously
when an excessive current flows due to a short
in the AC line.
CAUTION:
The CBR1 and CBR2 functions must not
be deactivated under any circumstances.
CBR1
NF NF2
[2] Protection by L2 and L4 (fixing heater
lamps) overheating prevention circuit
Control
section
1. Protection by software
The output voltage from TH1 (fixing tempera-
ture sensor 1) is read by the CPU. If this volt-
age is abnormal, L2 (fixing heater lamp 1), and
L4 (fixing heater lamp 3), and RL1 (main relay)
are turned OFF.
CAUTION:
Do not change the gap between the roller
and TH1. When repl-acing TH1, check the
specified mounting dimensions.
The RL1 function must not be deactivated
under any circum-stances.
S-10
ACDB
CB
RL
driver
section
L2
AC
driver
section
L4
RL1
RL1
TS1